1. Field of the Invention
The present invention generally relates to a current programming apparatus, a matrix type display apparatus, a current programming method, and a drive method of a matrix type display apparatus, and more particularly to ones suitably used for an active matrix type display apparatus using current based driven display elements.
2. Description of Related Art
In an active matrix type display apparatus using electroluminescent elements, a current writing type circuit writing a drive current of a light emitting device into the drive circuit of each pixel to make the drive circuit store the drive current has been used. In the present specification, such an operation of writing a drive current into each pixel of a matrix type display apparatus to make the drive circuit store the drive current is called as current programming, and the circuit for the current programming is called a current programming circuit.
In FIG. 18 of United States Patent Published Application No. 2002/0195964, a current programming circuit holding a current flowing in a data line as a gate-source voltage of a transistor is disclosed. Moreover, in the document, it is mentioned that gradation displays of black and low luminance levels can be improved by flowing the current into the direction of cancelling a writing current at the time of writing data into the current programming circuit.
When a conventional current writing type pixel circuit is used, there is a case where an operation of writing an image data current cannot be stably performed in each pixel circuit. The details of the case are described in the following, but the cause of the case is the dispersion of the threshold value of the drive transistor of each pixel.